Second and third year typically eat first year sales, and then the slow decline starts. Unless this gen is different from most, the ps4 should easily do over 80 million. Sony will never beat the ps2, it's sold 155,000,000. I think it could do ps sales, but no one ever thought that it would ps2, very few people did.

I don't think anything ever will. PS2 had everything going for it.

Accessible, popular, by far the most games, well known to the general non-gamer public, was an affordable DVD player and no competition to speak off. It even had the luck of a successor that stumbled out of the gate to grant it longer life and relevance. The wind was right in it's sails, it was perfect. The system put up great numbers for it's entire life, having the most extreme legs ever, which lasted 12 years! PS4 has some of these things going for it as well, but not everything, and not in the same capacity. I never thought PS4 would beat it at any time. Also, it beating the PS3 by 2:1 now means little, because the PS3 took a while to get into gear.

The PS3 can't follow up the PS2's success into the new generation, and the same way I think the PS4 can't. Life expectancy of hardware will be shorter again. I'd say PS4 end with a little over 100m, like the Wii and PS1 did.

No way to say for sure either way really.

None know the growth gaming will see world wide on the next few years. None have a clue what Chinese console market might look like in a few years.

PS4 could get a 100 price cut each year till its 99 for all we know. Given early sales dominance, it can. None know or can know if it will.

Its sales at 399 are insane, given that fact none of any intelligence should ever dismiss the chance.

110M is my guess

Im going to say that it wont only because I think we will be a shorter gen than last. The writing was on the wall when they went with mid end components as opposed to the high end of the past.

Not selling more then 100 million prediction is as crazy as predicting ps4 will outsell ps2

The number of cross-gen games proove that devs was not ready for this gen,i wouldn't be surprised if this gen will last more then last gen

Wah? It's at 18.5 million now, emerging markets are way better now than before (Sony showed us that PS4 has sold twice as much in Asia excluding Japan than the PS2 had in the same point in its life), Japanese support is just starting to pick up, It hasn't even reached its peak yet, so we should expect years higher than this in the future (it did 14 million this calendar year.)

How do you explain the 100 million figure?

I'll wait for End of March to get a better picture. But here's a few thing that make me believe it's still to close.
1st. PS2 released in Japan 7 months BEFORE it did anywhere else, so the numbers are not quite the same.
2nd PS4 released in Japan 3 months AFTER it was released everywhere else, so again numbers are not the same.
Taking all that in consideration PS4 would have to sell somewhere around 400k-500k a week on avarage untill End of March to be on Par with PS2. You have Bloodbourne & The Order 1886 coming out before then (unfortunately The witcher 3 won't) and a lot of Tax returns Usally in March (at least in US) I see it being very close to Par with PS2 come end of March,